Programming model for synchronizing browser caches across devices and web services

ABSTRACT

A computer user may use a computing environment comprising a set of computers that respectively feature a web browser having a browser cache containing many types of data objects, including application resources and user-generated data files. However, the contents of a browser cache significantly contribute to the computing environment of a computer, and the computing environments presented by each computer may diverge, providing an inconsistent computing environment. Instead, the contents of browser caches of the computers comprising the computing environment may be synchronized across computers. Additionally, the browser cache may be synchronized with the other data objects of a computing environment (such as relevant portions of the filesystem); the synchronizing may be implemented as an out-of-browser process executing independently of the applications, and even when the browser is not executing; and the synchronization may be exposed through a programmatic access with which web applications may interact.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of and claims priority to U.S.patent application Ser. No. 12/402,366, filed Mar. 11, 2009 and alsotitled “Programming Model for Synchronizing Browser Caches AcrossDevices and Web Services,” the entirety of which is incorporated byreference as if fully rewritten herein.

BACKGROUND

A webserver often stores a set of data objects, such as HTML pages,media objects, data stores, and executable scripts, that are provided toa web browser and rendered thereby to present a set of web pagescomprising a website. Web browsers typically include a browser cachewhere received items may be stored for reuse in subsequently renderedweb pages, thereby improving the performance of the web browser,economizing the resources of the webserver, and optionally providinglimited capabilities to render the web pages when the webserver cannotbe accessed. In contrast with other types of data objects within acomputer system (such as user documents, application and operatingsystem binaries, and application configuration information), the dataobjects contained in the browser cache have typically been regarded astemporary and disposable.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key factors oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

Developments in web technologies have resulted in more sophisticatedtypes of websites, which may incorporate web applications that executewithin the web browser. The data objects comprising such websites andweb applications are often stored in the browser cache, and it may bedesirable to enable the rendering of such websites and the execution ofsuch web applications when the webserver is inaccessible, such as whenthe web browser is not connected to a network or when the webserver isoffline. Such data objects may also be stored in several types ofbrowser caches (e.g., an application cache that stores applicationresources of a browser-hosted application and a content cache thatstores data objects retrieved from websites, such as HTML documents andimages.)

Contemporary users often utilize a set of computers (e.g., a portablecomputer, a workstation, and a cellphone device), and these computersmay collectively present to the user a computing environment, such asthe user's documents, installed applications, application and operatingsystem configuration information, user profiles, representations ofvarious individuals (e.g., contacts stored in a directory), etc.Moreover, particular aspects of these computers may be synchronized toimprove the consistency of the computing environment across all suchcomputers. However, respective computers may comprise a browser having abrowser cache, the contents of which may differ as the user interactsdifferently with each computer. If the contents of the browser cacheinclude an expanding set of significant data objects, such asapplications available offline and saved user documents, then thedivergence of such web caches among such computers may lead tocomputer-specific differences, such as inconsistent sets of availableapplications, conflicting versions of stored documents, anddiscrepancies in media libraries.

In order to reduce such inconsistencies and version conflicts, thebrowser caches of such computers may be synchronized. Among a set ofcomputers sharing a computing environment, a computer may be configuredto monitor the state of its browser cache for alterations, and tosynchronize with the browser caches of the other computers according tovarious synchronization policies. This browser cache synchronization mayalso be included in the synchronization of the general computingenvironment among such computers, thereby improving the efficiency ofthe synchronization process and economizing computing resources. Inaddition, a programmatic interface may be provided to permitapplications executing in the web browser to interact with the browsercache synchronization, such as by requesting the synchronization ofvarious data objects and by identifying information about thesynchronization policies of the browser cache. By maintaining theconsistency of the browser caches of the various computers utilized bythe user, these techniques may promote the consistency of the user'sdata objects and the computing environment.

To the accomplishment of the foregoing and related ends, the followingdescription and annexed drawings set forth certain illustrative aspectsand implementations. These are indicative of but a few of the variousways in which one or more aspects may be employed. Other aspects,advantages, and novel features of the disclosure will become apparentfrom the following detailed description when considered in conjunctionwith the annexed drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a component block diagram illustrating an exemplary scenarioinvolving a set of computers featuring browsers having browser caches.

FIG. 2 is a component block diagram illustrating an exemplary scenarioinvolving a set of computers featuring browsers having synchronizablebrowser caches.

FIG. 3 is a component block diagram illustrating an exemplary systemconfigured to synchronize a browser cache of a browser on a computerwith a remote store of a remote computer

FIG. 4 is an illustration of an exemplary computer-readable mediumcomprising processor-executable instructions configured to embody one ormore of the provisions set forth herein.

FIG. 5 is an illustration of an exemplary interaction of a computingenvironment host with various computing environment rendering devices.

FIG. 6 illustrates an exemplary computing environment wherein one ormore of the provisions set forth herein may be implemented.

DETAILED DESCRIPTION

The claimed subject matter is now described with reference to thedrawings, wherein like reference numerals are used to refer to likeelements throughout. In the following description, for purposes ofexplanation, numerous specific details are set forth in order to providea thorough understanding of the claimed subject matter. It may beevident, however, that the claimed subject matter may be practicedwithout these specific details. In other instances, structures are shownin block diagram form in order to facilitate describing the claimedsubject matter.

In the field of a computing, a webserver may provide to various visitorsthe content of web pages. In earlier generations of websites, suchcontent typically involved only simple types of data objects, such asHTML documents, graphics incorporated in such HTML documents, andclient-side JavaScript scripts. These data objects were delivered to aweb browser that rendered the web pages comprising the website on behalfof a user.

Early in the development of web browsers, a browser cache was developedwhere some or all such data objects might be stored upon receipt inorder for later re-use, thereby improving the performance of the webbrowser by avoiding redundant downloading of the data object andeconomizing the consumption of computing resources on the server. Thedata objects stored in the browser cache might also be used to render arepresentation of the content if the server was inaccessible, e.g., ifthe server was offline or if the computer was not connected to anetwork. While the caching of such data objects may have improved theperformance of the web browser by reducing redundant network transfers,these data objects were regarded as temporary and disposable. Manybrowsers include an option to delete the contents of the browser cacheas a temporary space-saving mechanism, since the items may often beobtained again during the user's next visit to the website.

Contemporary websites often involve more advanced types of content thanin earlier generations of web development. In particular, a website mayincorporate one or more applications that include executable binaries,data sources, and user-data objects, such as user-generated documents.These applications may also involve a diverse set of data objects thatmay be used by the web browser in presenting the application, and thatmay be stored in the browser cache. Moreover, the browser cache maystore data objects that may be used to provide access to certain aspectsof a website while the website is inaccessible (e.g., when the computeris not connected to a network, or when the website is offline.) In viewof these expanded capabilities, the data objects stored in a browsercache comprise a significant portion of the user's computingenvironment. Contemporary browsers may also provide multiple caches ofdifferent types; e.g., data objects comprising applications resources ofan application that may execute in a web browser may be stored in abrowser application cache, while data objects retrieved from visitedwebsites, such as HTML documents and images embedded therein, may bestored in a browser content cache. Both types of caches may promote theperformance of the web browser in a similar manner, but the storing ofresources in particular caches may provide additional advantages (e.g.,a user may be able to request an emptying of the content cache whilepreserving the contents of the application cache.)

Another trend in modern computing environments involves a growing scopeof computers that a user may utilize. For example, a user may oftenutilize a personal workstation, a portable computer of a notebook, palm,or pocket form factor, a cellphone, a media player, a camera, and agaming console. While these computers may have specialized purposes andscenarios, the user may regard all of them as together comprising thecomputing environment. Moreover, the computing environment may comprisea large and diverse set of data objects (e.g., media objects, documents,applications, and operating system preferences), and these data objectsmay be shared across all such computers. For example, these data objectsmay be automatically synchronized to provide a more consistent userexperience, so that a change to the computing environment on onecomputer (e.g., the addition of new media objects or applications, oralterations to a document) may be automatically propagated throughoutthe computing environment.

FIG. 1 illustrates an exemplary scenario 10 where user 12 may operate aset of computers, including a workstation 14, a notebook computer 28,and a cellphone device 30, that share a computing environment 18 storinga set of data objects, e.g., a set of documents 32. Each computer isalso equipped with a browser 16 that may be used to render anapplication 22 comprising a set of data objects 24 that may be deliveredto the respective computers and stored in a browser cache 20 associatedwith the browser 16. The data objects 24 may include, e.g., anapplication binary comprising the logic and user interface of theapplication 22, an application configuration that stores varioussettings and preferences selected by the user 12, and various documentscreated with the application 22, which may be presented to the user 12in the browser 16 as a user document 26. Additional data objects may bestored in the computing environment 18 but outside of the browser cache20, such as a set of documents 32. Moreover, the computing environments18 of these computers may share some or all of data objects; e.g., thedocuments 32 stored as data objects in the computing environment 18 maybe shared among the computers for accessibility on all of the computersacross which the computing environment 18 is shared.

However, problems may arise if each of these various computers comprisesa browser having a browser cache, and if such browser caches incorporatedata objects that comprise a significant portion of the user's computingenvironment. Because the browser caches in earlier generations ofbrowsers only stored temporary and disposable data objects, even if thedata objects in the computing environment are synchronized, the browsercaches of the computers may not be included in this synchronization.Accordingly, the browser caches of various computers that comprise theuser's computing environment may diverge, leading to different computingenvironments on different computers (e.g., different versions of adocument stored in the browser cache, or different sets ofbrowser-stored applications that may be available on differentcomputers.) As further illustrated in the exemplary scenario 10 of FIG.1, even if the documents 32 and other data objects in the computingenvironment 18 are automatically synchronized among the computers, thecontents of the respective browser caches 20 may fall out ofsynchronization. As a first example, the data object 24 comprising afirst document (“DOC 1”) might exist in different versions in eachcomputer, which might occur if the document were updated at differenttimes on the different devices but not synchronized. As a secondexample, data objects 24 may be present in one browser cache 20 but notin another browser cache 20; e.g., the data object 24 named “DOC 3” isincluded in the browser cache 20 of the workstation 14, but not in thebrowser cache 20 of the notebook computer 28. As a third example, anapplication 22 may be stored for offline access in some computers, butnot in other computers; e.g., in this exemplary scenario 10, the“Application” application 20 is stored for offline access on theworkstation 14 and the notebook computer 28, but not on the cellphonedevice 30. While some of these discrepancies might arise at theselection of the user 12 (e.g., an instruction from the user 12 toexclude the application 22 from the cellphone device 30) or based onlogical rationale (e.g., an inability to execute the application 22 withthe cellphone device 30 due to storage space, performance, or hardwarelimitations), in other cases these discrepancies might be undesirableand avoidable, but may nevertheless arise due to the absence of amechanism to synchronize the browser caches 20 of the computerscomprising the computing environment of the user 12.

FIG. 2 illustrates an exemplary scenario 40 featuring an embodiment ofthis technique. In the exemplary scenario 40 of FIG. 2, the workstation14, notebook computer 28, and cellphone device 30 may again respectivelycomprise a browser 16 coupled with a browser cache 20 configured tostore data objects 24, such as may belong to an application 22. Thesecomputers may also collectively comprise a computing environment 18 thatis shared across all such computers containing a set of data objects(such as documents 32) to be synchronized among such computers in orderto present a more consistent computing environment to the user. However,in this exemplary scenario 40, one or more of the computers may alsocomprise an exemplary system 42 configured to synchronize the browsercache 20 of a browser 16 of the respective computer with a remote storeof a remote computer, such as a browser cache 20 of a browser 16 ofanother computer. The exemplary system 42 may comprise a browser cachemonitoring component 44, which may monitor the browser cache 20 that isconfigured to detect a writing of a data object 24 to the browser cache20, such as the creation, editing, or deletion of a cached data object24. The exemplary system 42 may also comprise a browser cachesynchronizing component 46, which may be configured, upon the browsercache monitoring component 44 detecting the writing, to synchronize thebrowser cache 20 with the remote store (e.g., the browser cache 20 ofanother computer.) As a first example, the browser cache monitoringcomponent 44 implemented in the cellphone device 30 may detect thewriting a recent version of the “DOC 1” data object 24 to the browsercache 20, and may deliver the data object 24 to the browser cache 20 ofthe notebook computer 28 (e.g., by either directly interacting with thebrowser cache 20, by providing the data object 24 to the browser cachesynchronizing component 46 of the notebook computer 28 for writing toits browser cache 20, etc.) The browser cache monitoring component 44 ofthe notebook computer 28 may in turn detect the writing of the “DOC 1”data object 24 (replacing the earlier 1.1 version of the data object24), and the browser cache synchronizing component 46 may deliver theupdated data object 24 to the browser cache 20 of the workstation 14.

As a second example illustrated in FIG. 2, the browser cache monitoringcomponent 44 may detect the writing of the “DOC 3” data object 24 andits absence from the browser cache 20 of the notebook computer 28, andupon this detection, the browser cache synchronization component 46 ofthe workstation 14 may deliver the “DOC 3” data object 24 to the browsercache 20 of the notebook computer 28. As a third example, the browsercache monitoring component 20 of the notebook computer 28 may detect thestoring of the data objects 24 comprising the application resources ofthe application 22, and the browser cache synchronizing component 46 ofthe notebook computer 28 may, upon detecting the absence of such dataobjects 24 from the browser cache 20 of the cellphone device 30, sendthese data objects 24 to the cellphone device 30. In this manner, thebrowser caches 20 of the various computers may be brought intosynchrony, thereby presenting the user with a consistent computingenvironment (including the current version of the “DOC 1” data object24, the presence of the “DOC 3” data object 24, and the availability ofthe application 22 on all computers.)

More generally, and in view of these scenarios, FIG. 3 presents anexemplary embodiment 42 of the techniques discussed herein as anexemplary system 42 configured to synchronize a browser cache 20 of abrowser 16 on a computer 52 with a remote store 56 of a remote computer54. The exemplary system 42 may comprise a browser cache monitoringcomponent 44, which may be configured to detect a writing of at leastone data object 24 in the browser cache 20, and a browser cachesynchronizing component 46, which may be configured, upon the browsercache monitoring component 44 detecting the writing, to synchronize thebrowser cache 20 with the remote store 56. The exemplary system 58 maycomprise, e.g., a set of instructions stored in a memory 58 of thecomputer 52 and executable on a processor 60 in order to support thebrowser cache 20 and the synchronization of the computing environment ofthe computer 52 with other computers (such as the remote computer 54)utilized by a particular set of users.

Another embodiment of these techniques involves a computer-readablemedium comprising processor-executable instructions configured to applythe techniques presented herein. An exemplary computer-readable mediumthat may be devised in these ways is illustrated in FIG. 5, wherein theimplementation 70 comprises a computer-readable medium 72 (e.g., a CD-R,DVD-R, or a platter of a hard disk drive), on which is encodedcomputer-readable data 74. This computer-readable data 74 in turncomprises a set of computer instructions 76 configured to operateaccording to the principles set forth herein. In one such embodiment,the processor-executable instructions 76 may be configured to implementa system configured to synchronize a browser cache of a browser on acomputer with a remote store of a remote computer, such as the exemplarysystem 42 of FIG. 3. Many such computer-readable media may be devised bythose of ordinary skill in the art that are configured to operate inaccordance with the techniques presented herein.

The techniques discussed herein may be devised with variations in manyaspects, and some variations may present additional advantages and/orreduce disadvantages with respect to other variations of these and othertechniques. Moreover, some variations may be implemented in combination,and some combinations may feature additional advantages and/or reduceddisadvantages through synergistic cooperation. The variations may beincorporated in various embodiments (e.g., the exemplary system 42 ofFIG. 3) to confer individual and/or synergistic advantages upon suchembodiments.

A first aspect that may vary among embodiments of these techniquesrelates to the type of synchronization that may be performed between thebrowser cache 20 and the remote store 56. The process of synchronizingdata objects may have many variables that may be differently adjusted tosuit different scenarios. As a first example, the synchronization may betriggered by many events. In one such embodiment, the synchronizationmay be triggered promptly after the browser cache monitoring component44 detects a writing of a data object 24 to the browser cache 20. Whileprompt synchronization may provide a high degree of synchrony betweenthe browser cache 20 and the remote store 56, this triggering may beinefficient, e.g., by establishing a connection between the computer 52and the remote computer 54 upon each writing, and/or by establishing aseries of connections and data transfers in a short timeframe for a dataobject 24 that is updated several times in a short time frame. Inanother such embodiment, the synchronization may be triggered upon thebrowser monitoring component 44 detecting the writing, but after aparticular threshold has been met, e.g., after a defined thresholdperiod has elapsed without further writing to the browser cache 20,and/or after a defined threshold amount of data has been written to thebrowser cache 20. Alternatively or additionally, a synchronizing may betriggered by the remote computer 54; e.g., the remote computer 54 maysent a notification to the computer 52 to synchronize the browser cache20 with the remote store 56, and the browser cache synchronizingcomponent 46 may be configured, upon receiving the notification from theremote computer 54 to perform this synchronization. This type ofconfiguration may be advantageous between computers having a peerrelationship, e.g., two computers wherein the browser cache 20 of eithercomputer 52 may be altered. As another alternative, the synchronizingmay be triggered periodically, such as at a predetermined time on aweekly basis or after a certain amount of time has elapsed since thelast synchronization. As yet another alternative, the synchronizing maybe triggered based on other factors, such as when the processor 60 isdetected to have been idle for a threshold period of time, or when anavailability of network bandwidth is detected.

As a second variation of this first aspect, the synchronization mayoccur in many ways. As a first example, the computer 20 may simplydeliver to the remote computer 54 any data objects 24 that change on thecomputer 20, without examining the contents of the remote store 56. Thisconfiguration may be suitable, e.g., where the remote computer 54comprises an archival server that only receives updates from thecomputer 52. As a second example, the browser cache synchronizingcomponent 46 may enquire as to the contents of the remote store 56 ofthe remote computer 54, and may compare respective data objects 24 todetermine the data objects 24 that are missing or outdated in the remotestore 56 and due for updating. Alternatively, the browser cachesynchronizing component 46 may deliver a list of the contents of thebrowser cache 20 to the remote computer 54 for comparison with thecontents of the remote store 56, and may receive from the remotecomputer 54 a list of operations to be performed in order to synchronizethe browser cache 20 and the remote store 56. In either embodiment, thiscomparing may take into account many factors, e.g., the modificationdates of the data objects 24, the sizes or types of the data objects 24,a version identifier attributed to various data objects 24, and/or ahashcode representing the contents of the data objects 24. The browsercache synchronizing component 46 may then send to the remote computer 54the data objects 24 that are to be delivered in order to synchronize thebrowser cache 20 and the remote store 56. Alternatively or additionally,the browser cache synchronizing component 46 may also request dataobjects 24 that are newly stored or more recently updated on the remotecomputer 54, and may store such data objects 24 upon receipt in thebrowser cache 20. Alternatively or additionally, if a data object 24 isfound to have changed in both the browser cache 24 and the remote store56, the browser cache synchronizing component 46 and/or the remotecomputer 54 may determine whether to select one of the representationsof the data object 24 as authoritative and may replace thenon-authoritative representations. Alternatively, it may be possible tomerge the representations of the data object 24 to produce a hybrid dataobject 24 containing all such changes, and to replace both instanceswith the hybrid data object 24.

One feature of this second variation that illustrates some of thevariable complexity of synchronization relates to the discovery of dataobjects in the remote store 56 that are not present in the browser cache20. Such data objects 24 might exist if either newly stored in theremote store 56 since the last synchronization, or if such data objects24 were removed from the browser cache 20. In one such embodiment, ifthe browser cache synchronizing component 46 detects a data object 24 inthe remote store 56 that is not present in the browser cache 20, it mayrequest the remote computer 54 to remove the data object 24 from theremote store 56 (thereby presuming a removal from the browser cache 20.)Conversely, the browser cache synchronizing component 46 may beconfigured to receive requests from the remote store 56 to remove dataobjects 24 from the browser cache 20 that have been removed from theremote store 56, and may act accordingly to maintain synchrony.Alternatively or additionally, the browser cache monitoring component 44may endeavor to detect a removing of at least one removed data object 24in the browser cache 20, and the browser cache synchronizing component46 may then request the remote computer 54 to remove the data object 24from the remote store 56 (thereby presuming a new addition to the remotestore 56.) In yet another embodiment, the browser cache monitoringcomponent configured to detect a removing of at least one removed dataobject 24 from the browser cache 20, and may request the removal of suchremoved data objects 24 from the remote store 56. Any data objects 24thereafter identified in the remote store 56 may be presumed to havebeen recently added to the remote store 56. In yet another embodiment,the browser cache 20 and/or the remote store 56 may maintain a journalof modifications to the respective data object stores, and may examineor compare such journals to determine an accurate synchronizationoperation.

As a third variation of this first aspect, these techniques may beselectively applied to particular data caches offered by the webbrowser. Because data objects received by a web browser may be useful indifferent contexts (e.g., application resources belonging to anapplication and content-type data objects that are used in the renderingof a web page, such as HTML documents, style sheets, and embedded mediaobjects), the web browser may store such data objects in differentcaches (e.g., an application cache configured to store applicationresources and a content cache configured to store content-type dataobjects.) The synchronization techniques related herein may be appliedto the contents of such caches in various ways. As a first example, thesynchronization may be applied uniformly to all data objects in all suchcaches. As a second example, the synchronization may be applied only toparticular caches configured to store data objects of more significantvalue (e.g., an application cache), and to disregard the contents ofdata caches configured to store less useful data objects. As a thirdexample, the synchronization may be applied differentially to suchcaches; e.g., an application cache may be synchronized in full and on afrequent basis, while a content cache may be synchronized only withregard to a portion of the data objects stored therein (e.g., dataobjects retrieved or accessed within a recent time frame), and may besynchronized on a less rigorous schedule.

Additional variations of this first aspect may relate to moresophisticated forms of synchronization. As a first example, the browsercache synchronizing component 46 and/or the remote store 56 may beconfigured to synchronize only a portion of the data objects 24, such asa subset of data objects 24 matching at least one synchronized dataobject criterion. For example, the browser cache synchronizing component46 may be configured to synchronize only data objects 24 comprising userdata files, and/or only data objects 24 comprising application binaries,and/or only data objects 24 belonging to a particular user orapplication, and/or only data objects 24 not exceeding a particular datasize. The browser cache synchronizing component 46 may thereforedisregard other data objects 24 stored in the browser cache 20 duringthe synchronization. As a second example, a synchronization policy maybe devised that describes various aspects of the synchronization, suchas the synchronization triggering policy (e.g., the set of circumstancesunder which a synchronization may begin), a synchronization type policy(e.g., a unidirectional synchronization vs. a bidirectionalsynchronization), a data object comparing policy (e.g., the criteria bywhich two representations of a data object are compared to detectdifferences), a data object type merging policy (e.g., the types of dataobjects 24 that may be merged and the logic for doing so), and/or a dataobject conflict resolution policy (e.g., the logic by which differingrepresentations of a data object 24 are resolved.) It may beadvantageous to define several synchronization policies describing avariety of forms of synchronization (e.g., a first synchronizationpolicy applied during an infrequent synchronization and a secondsynchronization policy applied during a frequent, incrementalsynchronization.) Moreover, the synchronization policies may be definedeither by the computer 52 or by the remote computer 54, depending on therelationship therebetween. Those of ordinary skill in the art may devisemany techniques for initiating and performing the synchronization of thebrowser cache 20 and the remote computer 54 while implementing thetechniques discussed herein.

A second aspect that may vary among embodiments of these techniquesrelates to the architecture of the implementation. As a first example,the browser cache monitoring component 44 and the browser cachesynchronizing component 46 may execute in various manners within thecomputer 52. In a first such embodiment, the browser cache monitoringcomponent 44 may be configured to execute on the computer 52 within thebrowser 16, e.g., as part of the browser 16 or a plug-in installedtherein. This implementation may be helpful if the browser cachemonitoring component 44 is primarily tasked with monitoring the browsercache 20 for changes in order to trigger a synchronizing by the browsercache monitoring component 46, because such changes may likely ariseonly when the browser 16 is executing. By contrast, and alternatively oradditionally, the browser cache synchronizing component 46 may beconfigured to execute on the computer 52 as a process outside of thebrowser 16, e.g., as a background service of the computer 52. This maybe advantageous because the synchronizing may occur independently of thebrowser 16, e.g., by synchronizing changed data objects 24 withoutinterfering with the rendering of web pages and the executing ofapplications 20 by the browser 16, and by permitting the synchronizingof the browser cache 20 with the remote store 56 to occur when suchapplications 20 are not executing, and even if the browser 16 is notexecuting. For example, when the computer 52 is connected to a networkbut when the user 12 is not using the browser 16 (e.g., when thecomputer 52 is idle), the browser cache synchronizing component 46 mayretrieve some updated data objects 24 from the remote store 56 and storethem in the browser cache 20, and such objects may be used in thebrowser 16 when the user 12 requests to use these data objects 24 (e.g.,invokes an application 22 incorporating such web objects 24), even ifthe computer 52 is in an offline state.

As a second example of this second aspect, the architecture of theembodiments of these techniques may account for the actions of otherprocesses within the computer 54 while implementing the featuresdescribed herein. For example, it may be advantageous to implement thebrowser cache synchronizing component 46 as a process executing outsideof the browser 16, but this independence may permit a competitiveinterference of these two processes. As a first example, the browsercache synchronizing component 46 may attempt to replace a data object 24that is in use by the browser 16, causing a data violation error. As asecond example, the browser cache synchronizing component 46 and thebrowser 16 may each update a data object 24, and if an objectsynchronization construct is not used, a race condition may arise,resulting in a loss of data and potential logical problems. In order toavoid such problems and improve the implementation of these techniques,the browser cache monitoring component 44 and/or the browser cachesynchronizing component 46 may respect the actions of other processes.As a first example, the browser cache synchronizing component 46 mayrequest an access lock (such as a semaphore or a mutex) on a data object24 before synchronizing the data object 24 with the remote store 56, andmay release the lock on the data object 24 upon completing thesynchronizing of the data object 24. Alternatively or additionally, thebrowser cache monitoring component 44 may be configured, upon detectingan updating of a data object 24 by the browser cache synchronizingcomponent 46 that is in use by the browser 16, to notify the browser 16of the availability of the updated data object 24, and the browser mayreload the updated data object 24 at a convenient moment in theoperation of the browser 16 (e.g., when the data object 24 is notactively in use.)

As a third example of this second aspect, the synchronizing performed bythe browser cache synchronizing component 46 may be included in abroader synchronizing of the computing environment 18 with the remotestore 56. In a first such implementation, two computers may share dataobjects 24 stored both within the browser cache 20 and stored outside ofthe browser cache 20 but within the computing environment 18 (e.g.,files stored in the filesystem of the computer 52, user profiles storedby the operating system, and records stored in a database.) Asynchronization process may be devised to synchronize a large anddiverse set of data objects 24 stored and accessed in many data objectsystems, including data objects 24 stored in the browser cache 20,during a single synchronization. This may be helpful, e.g., forpermitting a user 12 to specify a single synchronization policy to beapplied to all data objects 24 regardless of how such data objects 24are stored, and for permitting one component to perform thesynchronizing of such data objects 24 instead of implementing multiplesynchronization components that independently (and perhapsconflictingly) synchronize different sets of data objects 24.

In one such embodiment, the computing environment 18 may represent adeployable computing environment, and the remote computer 54 maycomprise a computing environment host. In order to reduce the complexvariety and decentralization of the objects comprising a contemporarycomputing environment, a deployable representation of the computingenvironment may be devised, where the objects comprising the computingenvironment are organized in a data object hierarchy, which may behosted by a computing environment host. This computing environment hostmay be configured to store a representation of the entire set ofcomputers that comprise the computing environment 18 of the user 12; tocoordinate the synchronization of the computing environment 18 amongsuch computers; to store an authoritative representation of thecomputing environment 18 (e.g., the particular representations of dataobjects 24 that carry priority in resolving version conflicts); and/orto manage the deployment of the computing environment 18 or a portionthereof to particular computers 52, such as newly added computers. (Itmay be appreciated that the remote store 56 in this scenario may notnecessarily correspond to a browser cache on the computing environmenthost 82, which may comprise a file server that does not even contain abrowser, but may instead, e.g., represent a portion of the filesystem ofthe computing environment host 82 allocated to store the deployablecomputing environment 84.) The data object hierarchy may be delivered tovarious devices to represent the same computing environment (includingthe same user profiles, applications, data files, etc.), and each devicemay render the computing environment in a consistent manner butcustomized based on the capabilities of the device (e.g., a hardkeyboard interface for receiving data entry from a keyboard deviceattached to a workstation, and a touchscreen software keyboard interfacefor receiving data entry from a cellphone device.) A user of thedeployable computing environment may therefore interact with thedeployable computing environment in a platform- and device-independentmanner, while also achieving at least some of the advantages overalternative accessing techniques, such as synchronous or asynchronousinvoking, batching of standard operations, and mobile agents. Moreover,if the data objects 24 comprising the computing environment 18 arerepresented in a uniform manner and managed in a consistent way withinthe deployable computing environment (regardless of the particular dataobject system through which such data objects 24 are accessed), a set ofservices may be devised to apply to all of the data objects of thecomputing environment. However, those of ordinary skill in the art maydevise many such scenarios in which the techniques discussed herein maybe applied.

FIG. 5 illustrates one such scenario 80, wherein the computingenvironment may be hosted by a computing environment host 82, which maystore and manage a deployable computing environment 84. The computingenvironment host 82 may also render the deployable computing environment84 in different ways on behalf of various devices, such as a cellphonedevice 86, a personal notebook computer 90, and a public workstation 94,and also on behalf of different types of users having different accessprivileges. The rendering of the computing environment thereforereflects a consistent computing environment across all devices thatexpose the same applications, user profiles, shell configuration, userdata objects, etc. Thus, a user may access a full-featured version 92 ofthe computing environment through a high-performance notebook computer,a stripped-down version 88 of the computing environment on a low-powercellphone device 86, and a browser-compatible and privacy-orientedversion 98 of the computing environment through a web browser 86 of apublic terminal 94. To the extent that the capabilities of each suchdevice support the rendering of the computing environment, a consistentuser interface and data set may be presented due to the rendering of thedeployable computing environment 84 adjusted to the capabilities of eachdevice. Updates to the computing environment may be propagated back tothe computing environment host 82, and may be automatically synchronizedwith other devices. The various devices may also cooperate by sharinglocally stored data with other devices, and by controlling or beingcontrolled by other devices. Hence, the computing environment maytherefore be devised and presented as a cloud computing architecture,comprising a device-independent representation (a “cloud”) expressed asa consistent rendering across all devices (“clients”) that form a meshof cooperating portals (with device-specific properties) to the samecomputing environment. Specifically with respect to the applications ofthe computing environment, the deployable computing environment 84 mayinclude a representation of the application set, the applicationresources, and the data objects created thereby. Moreover, the computingenvironment host 82 may apply services to the various objects comprisingthe data object hierarchy 32, and the common format in which the dataobjects are stored in the deployable computing environment 84 mayfacilitate consistent availability and application of the servicesregardless of the nature of the data objects applied thereto.

With reference to this second aspect, if the computer 52 features acomputing environment 18 representing a deployable computing environment84 managed by a computing environment host 82, the techniques discussedherein may be implemented with particular advantages related thereto. Asa first example, if the computing environment host 82 serves as theremote computer 54, it may be advantageous to represent the browsercache 20 as part of the computing environment 18. Moreover, if theremote store 56 comprises the representation of the deployable computingenvironment 84 managed by the computing environment host 82, then thesynchronization of the entire computing environment 18, including thebrowser cache 20, may be performed together. For example, a computingenvironment component may be devised that manages the synchronization ofa large set of data objects 24 of the computer 52 with the computingenvironment host 82, including data objects 24 stored within the browsercache 20 as well as data objects 24 stored in and accessible throughother data object systems, such as files in the filesystem,configuration information stored in the system registry, and userprofiles stored by the operating system. The synchronization may then beperformed uniformly on the contents of the browser cache 20 as well asthe rest of the computing environment 18, and other services (e.g., anauthenticating service and a compression service) may be devised anduniformly applied to all such data objects 24. Again, it may bedesirable to perform the synchronization of all such objects 24 as asingle synchronization process, and/or in a single component, such as acomputing environment component that synchronizes all data objects 24 ofthe deployable computing environment 84 with the computing environmenthost 82. Moreover, the computing environment host 82 may also handle thedelivery of such data objects to other computers that share thecomputing environment, such that each computer 54 may primarilycommunicate with the computing environment host 82 but may neverthelessreceive data objects 24 originally created or recently updated on othercomputers 54.

As a fourth example of this second aspect, the browser cache monitoringcomponent 44 and/or the browse cache synchronizing component 46 mayfeature a synchronization programmatic interface, which may permitapplications 22 executing within the browser 16 to interact with thesynchronizing of the data objects 24 in the browser cache 20. As a firstexample, the synchronization programmatic interface may permitapplications 22 to identify details of the synchronization, such as thedate of the last synchronization of a data object 24 and the source ofthe data object 24. In one such embodiment, the synchronizationprogrammatic interface may comprise at least one synchronization policydisclosing operation configured to disclose at least one property of atleast one synchronization policy of the synchronization, and at leastone synchronization policy setting operating configured to set at leastone property of at least one synchronization policy. For example, anapplication may be supplied by an application host that updates aparticular application resource on a fixed schedule, such as anantivirus software vendor that supplies a new antivirus definitiondatabase at midnight each Sunday. The application host may thereforeconfigure the application 22 to instruct the browser cache synchronizingcomponent 46, via the synchronization programmatic interface, to updatethe data object 24 comprising this application resource at thepredetermined time. The application 22 may also use the synchronizationprogrammatic interface to identify the date and time of the last suchsynchronization of the data object 24 (e.g., in order to notify a user12 if the virus definition database is out of date), and/or to restrictthe synchronization of the data object 24 only with trusted sourcesidentified by the application host (e.g., so that an virus definitiondatabase may only be retrieved directly from the antivirus softwarevendor.) Alternatively or additionally, the browser cache synchronizingcomponent 46 may expose a synchronization programmatic interfaceconfigured to invoke the browser cache synchronizing component 46 tosynchronize the browser cache 20 (or a portion thereof) with the remotestore 54. For example, an application 22 may be permitted to invoke asynchronizing of a particular data object 24 by the browser cachesynchronizing component 46 through an operation of the synchronizationprogrammatic interface (e.g., if a user of an antivirus applicationrequests a prompt updating of a virus definition database.)

Additionally, the synchronization programmatic interface may beimplemented in a familiar and well-established manner, which may permitapplications to utilize the interfaces conveniently and withoutsignificant redesign. For example, a web browser plug-in designed tosupport applications 22 executing in a web browser 16 may expose aJavaScript-based synchronization programmatic interface, e.g., as a setof operations that may be invoked in JavaScript to read and writevarious data objects 24 in the browser cache 20. Alternatively oradditionally, synchronization the programmatic interface may supporthigher-level languages, e.g., object-oriented languages such as Java andC#; may expose more sophisticated details of the computing environment,such as the scheduling of the synchronization service, the freshness andpolicies of the local cache, and the relationships of the computerscomprising the computing environment (e.g., which computer serves as thehost of an authoritative representation of a particular data object);and/or may include more sophisticated programming constructs that permitmore powerful programmatic access (e.g., event subscriptions and datafeeds that may notify applications of computing environment events, suchas the synchronization of a particular data object.) In this manner, theprogrammatic interface may expose a wide variety of aspects of thecomputing environment in a sophisticated manner, while also adhering tofamiliar programming models that may be readily adopted by developerswithout having to redesign or rewrite large portions thereof utilizingdifferent programming techniques. Those of ordinary skill in the art maydevise many architectures and features thereof while implementing thetechniques discussed herein.

A third aspect that may vary among embodiments of these techniquesrelates to data-object-specific features that may be included in variousimplementations thereof. As a first example, a data object 24 that anapplication 22 requests to be stored in the browser cache 20 may haveone or more unusual properties, such as a large data object or anumerous set of associated data objects. Some browser caches 20 may beunable to accommodate such caching. For example, a browser cache 20 mayimpose a size limit on particular data objects, and a particular dataobject 24 may be too large to store in the browser cache 20 (e.g., alarge database that may be provided for offline access by theapplication 22.) Instead, the browser 16 may be configured to store suchdata objects 24 outside of the browser cache 20 and in the computingenvironment 18, such as a file in a filesystem, and to store in thebrowser cache 20 a reference to the data object 24 stored outside of thebrowser cache 20. Moreover, the browser cache monitoring component 44may be configured to monitor the updating of the data object 24 storedoutside of the browser cache 20 along with the updating of data objects24 stored within the browser cache 20; and/or the browser cachesynchronizing component 46 may be configured to synchronize such dataobjects 24 stored outside the browser cache 20 along with the dataobjects 24 stored within the browser cache 20.

As a second example of this third aspect, a data object 24 stored in thebrowser cache 20 may comprise an application resource of an application22 configured to execute within the browser 16. The browser cachemonitoring component 44 and/or the browser cache synchronizing component46 may be configured to handle such data objects 24 in a particularmanner. In a first such scenario, the data object 24 may comprise anapplication installer package, which may be invoked to install theapplication 22 within the browser 16. The browser cache synchronizingcomponent 46 may therefore be configured, upon receiving the data object24 from the remote computer 54, to invoke the application installerpackage to install the application 22. As a second example, theapplication 22 with which the data object 24 is associated may beassociated with an application host, and may be configured to execute inan application host connection context, such as a connected context or adisconnected context. In one such scenario, the data object 24 maycomprise an offline application resource, and the application 22 may beconfigured to use the offline application resource when the application22 executes in a disconnected context. Those of ordinary skill in theart may devise many techniques for configuring the browser cachemonitoring component 44 and/or the browser cache synchronizing component46 with respect to particular types of data objects 24 whileimplementing the techniques discussed herein.

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

As used in this application, the terms “component,” “module,” “system”,“interface”, and the like are generally intended to refer to acomputer-related entity, either hardware, a combination of hardware andsoftware, software, or software in execution. For example, a componentmay be, but is not limited to being, a process running on a processor, aprocessor, an object, an executable, a thread of execution, a program,and/or a computer. By way of illustration, both an application runningon a controller and the controller can be a component. One or morecomponents may reside within a process and/or thread of execution and acomponent may be localized on one computer and/or distributed betweentwo or more computers.

Furthermore, the claimed subject matter may be implemented as a method,apparatus, or article of manufacture using standard programming and/orengineering techniques to produce software, firmware, hardware, or anycombination thereof to control a computer to implement the disclosedsubject matter. The term “article of manufacture” as used herein isintended to encompass a computer program accessible from anycomputer-readable device, carrier, or media. Of course, those skilled inthe art will recognize many modifications may be made to thisconfiguration without departing from the scope or spirit of the claimedsubject matter.

FIG. 6 and the following discussion provide a brief, general descriptionof a suitable computing environment to implement embodiments of one ormore of the provisions set forth herein. The operating environment ofFIG. 6 is only one example of a suitable operating environment and isnot intended to suggest any limitation as to the scope of use orfunctionality of the operating environment. Example computing devicesinclude, but are not limited to, personal computers, server computers,hand-held or laptop devices, mobile devices (such as mobile phones,Personal Digital Assistants (PDAs), media players, and the like),multiprocessor systems, consumer electronics, mini computers, mainframecomputers, distributed computing environments that include any of theabove systems or devices, and the like.

Although not required, embodiments are described in the general contextof “computer readable instructions” being executed by one or morecomputing devices. Computer readable instructions may be distributed viacomputer readable media (discussed below). Computer readableinstructions may be implemented as program modules, such as functions,objects, Application Programming Interfaces (APIs), data structures, andthe like, that perform particular tasks or implement particular abstractdata types. Typically, the functionality of the computer readableinstructions may be combined or distributed as desired in variousenvironments.

FIG. 6 illustrates an example of a system 100 comprising a computingdevice 102 configured to implement one or more embodiments providedherein. In one configuration, computing device 102 includes at least oneprocessing unit 106 and memory 108. Depending on the exact configurationand type of computing device, memory 108 may be volatile (such as RAM,for example), non-volatile (such as ROM, flash memory, etc., forexample) or some combination of the two. This configuration isillustrated in FIG. 6 by dashed line 104.

In other embodiments, device 102 may include additional features and/orfunctionality. For example, device 102 may also include additionalstorage (e.g., removable and/or non-removable) including, but notlimited to, magnetic storage, optical storage, and the like. Suchadditional storage is illustrated in FIG. 6 by storage 110. In oneembodiment, computer readable instructions to implement one or moreembodiments provided herein may be in storage 110. Storage 110 may alsostore other computer readable instructions to implement an operatingsystem, an application program, and the like. Computer readableinstructions may be loaded in memory 108 for execution by processingunit 106, for example.

The term “computer readable media” as used herein includes computerstorage media. Computer storage media includes volatile and nonvolatile,removable and non-removable media implemented in any method ortechnology for storage of information such as computer readableinstructions or other data. Memory 108 and storage 110 are examples ofcomputer storage media. Computer storage media includes, but is notlimited to, RAM, ROM, EEPROM, flash memory or other memory technology,CD-ROM, Digital Versatile Disks (DVDs) or other optical storage,magnetic cassettes, magnetic tape, magnetic disk storage or othermagnetic storage devices, or any other medium which can be used to storethe desired information and which can be accessed by device 102. Anysuch computer storage media may be part of device 102.

Device 102 may also include communication connection(s) 116 that allowsdevice 102 to communicate with other devices. Communicationconnection(s) 116 may include, but is not limited to, a modem, a NetworkInterface Card (NIC), an integrated network interface, a radio frequencytransmitter/receiver, an infrared port, a USB connection, or otherinterfaces for connecting computing device 102 to other computingdevices. Communication connection(s) 116 may include a wired connectionor a wireless connection. Communication connection(s) 116 may transmitand/or receive communication media.

The term “computer readable media” may include communication media.Communication media typically embodies computer readable instructions orother data in a “modulated data signal” such as a carrier wave or othertransport mechanism and includes any information delivery media. Theterm “modulated data signal” may include a signal that has one or moreof its characteristics set or changed in such a manner as to encodeinformation in the signal.

Device 102 may include input device(s) 114 such as keyboard, mouse, pen,voice input device, touch input device, infrared cameras, video inputdevices, and/or any other input device. Output device(s) 112 such as oneor more displays, speakers, printers, and/or any other output device mayalso be included in device 102. Input device(s) 114 and output device(s)112 may be connected to device 102 via a wired connection, wirelessconnection, or any combination thereof. In one embodiment, an inputdevice or an output device from another computing device may be used asinput device(s) 114 or output device(s) 112 for computing device 102.

Components of computing device 102 may be connected by variousinterconnects, such as a bus. Such interconnects may include aPeripheral Component Interconnect (PCI), such as PCI Express, aUniversal Serial Bus (USB), firewire (IEEE 1394), an optical busstructure, and the like. In another embodiment, components of computingdevice 102 may be interconnected by a network. For example, memory 108may be comprised of multiple physical memory units located in differentphysical locations interconnected by a network.

Those skilled in the art will realize that storage devices utilized tostore computer readable instructions may be distributed across anetwork. For example, a computing device 120 accessible via network 118may store computer readable instructions to implement one or moreembodiments provided herein. Computing device 102 may access computingdevice 120 and download a part or all of the computer readableinstructions for execution. Alternatively, computing device 102 maydownload pieces of the computer readable instructions, as needed, orsome instructions may be executed at computing device 102 and some atcomputing device 120.

Various operations of embodiments are provided herein. In oneembodiment, one or more of the operations described may constitutecomputer readable instructions stored on one or more computer readablemedia, which if executed by a computing device, will cause the computingdevice to perform the operations described. The order in which some orall of the operations are described should not be construed as to implythat these operations are necessarily order dependent. Alternativeordering will be appreciated by one skilled in the art having thebenefit of this description. Further, it will be understood that not alloperations are necessarily present in each embodiment provided herein.

Moreover, the word “exemplary” is used herein to mean serving as anexample, instance, or illustration. Any aspect or design describedherein as “exemplary” is not necessarily to be construed as advantageousover other aspects or designs. Rather, use of the word exemplary isintended to present concepts in a concrete fashion. As used in thisapplication, the term “or” is intended to mean an inclusive “or” ratherthan an exclusive “or”. That is, unless specified otherwise, or clearfrom context, “X employs A or B” is intended to mean any of the naturalinclusive permutations. That is, if X employs A; X employs B; or Xemploys both A and B, then “X employs A or B” is satisfied under any ofthe foregoing instances. In addition, the articles “a” and “an” as usedin this application and the appended claims may generally be construedto mean “one or more” unless specified otherwise or clear from contextto be directed to a singular form.

Also, although the disclosure has been shown and described with respectto one or more implementations, equivalent alterations and modificationswill occur to others skilled in the art based upon a reading andunderstanding of this specification and the annexed drawings. Thedisclosure includes all such modifications and alterations and islimited only by the scope of the following claims. In particular regardto the various functions performed by the above described components(e.g., elements, resources, etc.), the terms used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (e.g., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure which performs thefunction in the herein illustrated exemplary implementations of thedisclosure. In addition, while a particular feature of the disclosuremay have been disclosed with respect to only one of severalimplementations, such feature may be combined with one or more otherfeatures of the other implementations as may be desired and advantageousfor any given or particular application. Furthermore, to the extent thatthe terms “includes”, “having”, “has”, “with”, or variants thereof areused in either the detailed description or the claims, such terms areintended to be inclusive in a manner similar to the term “comprising.”

What is claimed is:
 1. A system that synchronizes a local browserapplication cache of applications presented within a browser on acomputer comprising a memory and a remote browser application cache of aremote device, the system comprising: a browser application cachemonitor comprising instructions stored in the memory that, when executedby the processor, causes the computer to detect a local update ofcontent of at least one application resource of at least one applicationrepresented in the local browser application cache that executes withinthe browser; a browser application cache synchronizer comprisinginstructions stored in the memory that, when executed by the browser,cause the computer to: responsive to the browser application cachemonitor detecting the local update, transmit the local update of thecontent of the at least one application resource to the remote devicefor application to the remote browser application cache; and responsiveto receiving, from the remote device, a remote update of at least onedata object of the remote browser application cache, apply the remoteupdate to the local browser application cache; and an applicationprovider that, responsive to a request by the application executingwithin the browser to access an application resource, provides theapplication resource from the local browser application cache to theapplication.
 2. The system of claim 1, wherein the browser applicationcache synchronizer responds to a request received from the remote deviceto synchronize the local browser application cache with the remotebrowser application cache, by synchronizing the local browserapplication cache with the remote browser application cache.
 3. Thesystem of claim 2, wherein: the local update detected by the browserapplication cache monitor further comprises a removal of at least oneremoved application resource in the local browser application cache, andthe browser application cache synchronizer transmits the local update tothe remote device as a request to remove the removed applicationresource from the remote browser application cache.
 4. The system ofclaim 1, wherein the browser application cache synchronizer synchronizesthe local browser application cache with the remote browser applicationcache according to a synchronization policy.
 5. The system of claim 4,wherein the synchronization policy is selected from a set ofsynchronization policies comprising: a synchronization triggeringpolicy; a synchronization type policy; a data object comparing policy; adata object type merging policy; and a data object conflict resolutionpolicy.
 6. The system of claim 4, wherein the synchronization policy isdefined by the remote device.
 7. The system of claim 1, wherein thebrowser application cache monitor further comprises a browser componentthat executes on the computer within the browser.
 8. The system of claim1, wherein the browser application cache synchronizer further comprisesa native process of the computer that executes outside of the browser.9. The system of claim 1, wherein: the local browser application cacheis included in a computing environment of the computer, and at least oneapplication resource is stored within the computing environment of thecomputer outside of the local browser application cache, and isrepresented in the local browser application cache as a reference to theapplication resource stored outside of the local browser applicationcache.
 10. The system of claim 9, wherein: the computing environmentfurther comprises a deployable computing environment deployed to thecomputer by a computing environment host that manages the computingenvironment; and the browser application cache synchronizer synchronizesthe computing environment with the computing environment host.
 11. Thesystem of claim 1, wherein the browser application cache synchronizerapplies the remote update to an application resource stored in the localbrowser application cache by: before updating the application resource,requesting an access lock on the application resource from the computer;and after applying the remote update to the application resource,releasing the access lock on the application resource.
 12. The system ofclaim 1, further comprising: a synchronization programmatic interfacecomprising: at least one synchronization policy disclosing operationthat discloses at least one property of at least one synchronizationpolicy, and at least one synchronization policy setting operation thatsets at least one property of at least one synchronization policy. 13.The system of claim 12, wherein the synchronization programmaticinterface further comprises a synchronization invoking operation thatinvokes the browser application cache synchronizer to synchronize thelocal browser application cache with the remote browser applicationcache.
 14. The system of claim 1, wherein at least one applicationresource stored in the local browser application cache further comprisesan application resource that is associated with an application thatexecutes within the browser.
 15. The system of claim 14, wherein: theapplication resource further comprises an application installer package,and the browser application cache synchronizer, responsive to receivingthe remote update of the application installer package from the remotedevice, invokes the application installer package to apply the remoteupdate to the local browser application cache.
 16. The system of claim14, wherein the application is associated with a web application hostand executes in an application host connection context selected from aset of application host connection contexts comprising: a connectedcontext, and a disconnected context.
 17. The system of claim 16,wherein: the application resource further comprises an offlineapplication resource, and the application further uses the offlineapplication resource when the application executes in a disconnectedcontext.
 18. A device that presents applications through a web browser,comprising: a processor; and a memory storing: a local browserapplication cache storing application resources of applicationspresented through the web browser; and instructions that, when executedby the processor, cause the device to provide a system comprising: abrowser application cache monitor that detects changes to content of theapplication resources of the applications stored in the local browserapplication cache of the web browser; and a browser application cachesynchronizer that synchronizes the local browser application cache ofthe web browser with a second browser application cache, by: responsiveto the browser application cache monitor detecting a change in thecontent of a selected application resource of the local browserapplication cache of the web browser, pushing the change of the contentof the application resource to the second browser application cache; andresponsive to receiving, from the second browser application cache, anupdate of a selected application resource of the second browserapplication cache, applying the update to the selected applicationresource of the local browser application cache of the web browser. 19.A method of presenting applications through a web browser of a devicehaving a processor and a local browser application cache comprisingapplication resources of applications presented by the web browser, themethod comprising: executing, by the processor, instructions that causethe device to: detect changes to content of the application resources ofthe applications stored in the local browser application cache of theweb browser; and synchronize the local browser application cache of theweb browser with a second browser application cache, by responsive to abrowser application cache monitor detecting a local update of thecontent of a selected browser application resource of the local browserapplication cache of the web browser, pushing the local update of thecontent of the browser application resource to the second browserapplication cache; and responsive to receiving, from the second browserapplication cache, a remote update of a selected browser applicationresource of the second browser application cache, applying the remoteupdate to the selected browser application resource of the local browserapplication cache of the web browser.
 20. The method of claim 19,wherein the device synchronizes the local browser application cache withthe second browser application cache through a browser applicationserver, by: pushing the local update of the browser application resourceto the browser application server for retransmission to the secondbrowser application cache; and receiving the remote update from thesecond browser application cache through the browser application server.21. A computer-readable storage medium having computer-readableinstructions stored thereon that, when executed by at least oneprocessor of a computing device, the computing device having a localbrowser application cache comprising application resources ofapplications presented by a web browser of the computing device,configure the computing device to: detect changes to content of theapplication resources of the applications stored in the local browserapplication cache of the web browser; and synchronize the local browserapplication cache of the web browser with a second browser applicationcache, by: responsive to a browser application cache monitor detecting alocal update of the content of a selected browser application resourceof the local browser application cache of the web browser, pushing thelocal update of the content of the browser application resource to thesecond browser application cache; and responsive to receiving, from thesecond browser application cache, a remote update of a selected browserapplication resource of the second browser application cache, applyingthe remote update to the selected browser application resource of thelocal browser application cache of the web browser.